Remove legacy root controller and views #5190

Job	Run time
Lint SCSS / Run Stylelint	21s
Lint Ruby / Run RuboCop	23s
Security Analysis / Run Brakeman	23s
Lint JavaScript / Run Standardx	14s
Dependency Review scan / dependency-review-pr	7s
Test Ruby / Run Minitest	7m 41s
Test JavaScript / Run Jasmine	35s
CodeQL SAST scan / Analyze	2m 2s
Lint Ruby / Run ErbLint	19s
Dependency Review scan / dependency-review-push	0s
	12m 5s

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